Call your obgyn. They will write you a note saying that it's ok to have dental work done. Then you'll need to set up an appointment with your dentist (they'll ask for the note) and that way you're prepared and hopefully feel more comfortable as well knowing your doctor gave you the ok. All dentists require a note from obgyn when the patient is pregnant.
Ice it. And get the dental work done, you don't want an infection, that is a much higher risk that a root cabal
Go and have rct done. It is okay to have dental work just no nitrous. I am a dental assistant but it is okay to have dental work. Ibuprofen is okay up until 23 weeks. Confkirm w your ob dr if you are high risk. Goodluck :)